1. Field of the Invention
The present invention relates to an electronic watch using a thermoelement as an energy source.
2. Description of the Related Art
Conventionally, there has been recently studied an electronic equipment using a thermoelement that develops an electromotive force based on the Seebeck effect as an energy source instead of a battery. For example, FIG. 9 is a diagram showing the structure of an electronic wrist watch (hereinafter referred to as "thermo-electric type wrist watch") with a thermoelement as an energy source. The thermo-electric type wrist watch includes a movement 901, a thermo-electric type generator 902, an electric energy battery, and a casing 903 of a wrist watch consisting of a metal bottom portion, a frame portion and a metal top portion. The thermo-electric type wrist watch thus structured is disclosed, for example, in Japanese Patent Unexamined Publication No. Sho 55-20483. However, a thermoelement module made from the viewpoints of a power capacity and downsizing or an electronic equipment using a thermoelement module have not yet come to practical use.
The thermoelement requires the structure for supporting both sides thereof, but assuming that its first support member is at a heat absorbing side whereas its second support member is at a heat radiating side, in the case where a difference in temperature is given such that a temperature at the heat absorbing side is higher than that at the heat radiating side, the transmission of heat within an n-type semiconductor and a p-type semiconductor is converted into a current so that an electromotive force can be obtained by output terminal portions at both ends thereof. Since the electromotive force increases with a difference in temperature, in order to obtain a larger difference in temperature for increasing the electromotive force, there is required that the structure, the material or the like of the support member is devised to enhance a heat absorption efficiency or a heat radiation efficiency. For achieving this, it is desirable that the first support member is brought in contact with a rear cap which is in contact with an arm that is a heat source, and the second support member is brought in contact with an outer packaging case which is in contact with an outside air.
However, the thermoelement is low in strength against an external force. In particular, since the n-type semiconductors and the p-type semiconductors are shaped in a slender column and are erected in a large number of alignments, if a force is applied to the thermoelement laterally with respect to a direction of the transmission of heat within the n-type semiconductor and the p-type semiconductor, there is a risk that the thermoelement is destroyed. Therefore, since the structure in which the first and second support bodies which support the thermoelement are brought in contact with outer packaging parts or the like, respectively, makes a shock resistance low, the thermoelement needs to be protected. Also, the structure in which the first and second support bodies are brought in contact with the outer packaging parts, respectively, makes it difficult to assemble the thermoelement and the outer packaging parts, which is a problem.